The monad I. Indices has been implemented.
See the dictionary for details.

The dyads I.@E. and I.@:comp and [: I. comp where comp
is one of = ~: < <: > >: E. ,are supported by special code,
as are the monads I.@~: I.@:~: [: I. ~: .
The following benchmarks demonstrate the improvements in time and space.